Bikota

A Bikont ("two flagella") is a eukaryotic cell with two flagella, as its name suggests. It is a division of eukaryotes.

Enzymes
Another shared trait of bikonts is the fusion of two genes into a single unit: the genes for thymidylate synthase (TS) and dihydrofolate reductase (DHFR) encode a single protein with two functions. The genes are separately translated in unikonts.

Relationships

  Ceratium hirundinella
 
Ceratium hirundinella
   
Some research suggests that a unikont (a eukaryotic cell with a single flagellum) was the ancestor of opisthokonts (Animals, Fungi and related forms) and Amoebozoa, and a bikont was the ancestor of Archaeplastida (Plants and relatives), Excavata, Rhizaria, and Chromalveolata. Cavalier-Smith has suggested that Apusozoa, which are typically considered incertae sedis, are in fact bikonts.

Relationships within the bikonts are not yet clear. Cavalier-Smith has grouped the Excavata and Rhizaria into the Cabozoa and the Archaeplastida and Chromalveolata into the Corticata, but at least one other study has suggested that the Rhizaria and Chromalveolata form a clade.

See also
Unikont
⇒ Heterokont


References
- Burki F, Pawlowski J (October 2006). "Monophyly of Rhizaria and multigene phylogeny of unicellular bikonts". Mol. Biol. Evol. 23 (10): 1922–30.
- Thomas Cavalier-Smith (2006). "Protist phylogeny and the high-level classification of Protozoa". European Journal of Protistology 39 (4): 338–348.
- Burki F, Shalchian-Tabrizi K, Minge M, Skjæveland Å, Nikolaev SI, et al. (2007). "Phylogenomics Reshuffles the Eukaryotic Supergroups". PLoS ONE 2 (8: e790): e790.

Further reading
- Stechmann A, Cavalier-Smith T (September 2003). "The root of the eukaryote tree pinpointed". Curr. Biol. 13   (17): R665–6.